Various advantages of the wind power generating system are widely known but it is also known that there are some disadvantages that prevent more wide spread use of wind power energy. One of the disadvantages is that the power output fluctuates a great deal because the wind speed is not constant and largely unpredictable. There are areas where wind blows more or less constantly. However, a larger majority of areas experience wind of highly fluctuating wind speeds. In spite of extensive research efforts, conventional wind power generating systems are not able to produce a useful amount of electric energy when the wind speed drops below a certain level. In most cases, a useful amount of electricity may not be produced during a large part of each day.